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Type of the Paper (Article, Review, etc.)

Study into commercially available soil wetting agent’s vs an Australian
manufactured salicylic acid-based product

Author Jerry Spencer BSc Hons, and Cameron Smith CSTM Course Superintendent Sanctuary Cove
CC formerly Bonnie Doon G.C
jerry@gilbasolutions.com

Abstract:
The use of soil wetting agents is becoming increasingly popular because of their potential effect on
improved water efficiencies and improvements in turf quality. Therefore, this research was
conducted to observe the effect of nine soil wetting agents on Turf Quality, Soil Moisture content,
and water penetration times compared with a proprietary salicylic acid-based product and an
untreated control.
On high sand-content root zones, wetting agents are applied to turfgrasses to help manage the
symptoms of hydrophobic soils and the uniformity of soil moisture through the profile.
A completely randomized block design (CRBD) with six replicates was used to set up the
experiment. The trial ran for 163 days on a creeping bentgrass (Agrostis tenuis var MacKenzie) at
Bonnie Doon Golf Club in Sydney, Australia.
In this trial, all products were applied at label rates and then washed in as per their labels. Turf
Quality, soil moisture contents, organic matter content and water penetration times were
significantly impacted by the application of soil wetting agents to the soil.



Results:

1. The null hypothesis is that none of these products makes any difference to turf quality, root
growth, soil volumetric moisture content at 37 or 75mm, or water penetration.
2. Over the duration of the trial, there were no significant differences between any of the
Treatments and the untreated Control in relation to Turf Colour apart from the Tricure
Treatment. This had a significantly lower Turf Colour than the Control.
3. Hydrahawk, Tour Turf ELL, Hydroforce Ultra and the Gilba proprietary mix all had
significantly higher Turf Colour than Tricure.
4. At the 37mm depth Penterra was the only treatment that gave a significantly lower soil
moisture content than the control.
5. H2Pro Trismart had significantly higher soil moisture levels than Hydrahawk, Tour Turf
ELL, Penterra, and Tour Turf FTE treatments.
6. At 75 mm, Penterra had a significantly lower moisture content than the Control. Penterra
was also significantly lower than the Tricure and H2Pro Trismart treatments.
7. With the Water Drop Penetration Test (WDPT) at the 1cm depth there were significant
differences between the treatments. H2Pro Trismart had significantly faster WDPT than
Hydrahawk.
8. At a 2cm depth the H2Pro Trismart and Tour Turf FTE treatments had significantly faster
WDPT compared to Hydrahawk. There were no significant differences between any of the
other treatments.
9. At the 3cm depth the WDPT of the Gilba Proprietary, the Hydroforce Ultra and the Tour Turf
ELL treatments were all faster compared to the Hydrahawk treatment.

10. The HydroForce Ultra was the only treatment that had a significantly higher organic matter
content than the Control.
Keywords: biostimulant; turfgrass; organic matter; root growth; wetting agent; soil water; salicylic acid

1. Introduction

Effectively utilising water is key to maintaining healthy, disease-free playing surfaces. Too much
water and it tends to produce a soft, disease prone surface with its associated increase in
management costs. These are seen as more frequent fungicide applications and a shallower root
system that leads to turfgrass wilting as soon as it comes into any period of moisture stress.

In contrast, too little water, and turf tends to struggle and in a worst-case scenario die.

Soil water is vital to maintain optimal turfgrass growth and as we all become increasingly under
pressure due to climate change managing this valuable resource becomes increasingly important.

A huge amount of work has been carried out into the use of soil surfactants in turfgrass. The result
is that these are now widely used in the Australian turfgrass industry.

Manufacturers make numerous claims often without independent supporting data, so this trial was
designed to see if differences did exist in the performance between these.

Very little work has been done looking at the utilization of these in conjunction with salicylic acid.
The thinking behind this is to leverage with hydrological properties of a soil surfactant in
conjunction with the benefits of salicylic acid against both biotic and abiotic stresses.

https://www.swissgreen.ch/fileadmin/user_upload/swissgreen/public/Download/2023_H2Pro_TriSmart_registered_as_biostimulant_-_press_release.pdf


https://icl-growingsolutions.com/en-ie/turf-landscape/trials/h2pro-trismart-stri-australia/


https://icl-growingsolutions.com/en-gb/turf-landscape/trials/h2pro-trismart-biostimulant-trials-at-stri/



In recent years several plant health benefits have been shown with some of these soil wetting
agents. For example, in our 2022 trials, we showed that some soil wetting agents reduce dollar spot
incidence when used at label rates. In contrast others had little to no effect.

These plant health benefit claims are made as a direct result of the surfactant molecules being used.
As far as we are aware this trial will be the first time the plant health benefits of a high loading of
salicylic acid into a soil wetting agent will be trialled.

1.1 H2Pro TriSmart
A considerable amount of research has been carried out into the performance of H2pro TriSmart.

Four independent field trials, executed by the STRI in Bingley, UK, each with an 8 times treatment
replication, demonstrated that a H2Pro TriSmart program significantly improves turfgrass quality
traits.

A 2017 independent trial at the STRI Australia, Brisbane illustrated the value of utilising a wetting
agent programme on ultradwarf couch, to significantly improve surface quality and colour and to
reduce localised Dry spot. H2Pro TriSmart also maintained an improved surface quality with a 40%
water saving over control plots, demonstrating water use efficiency from a wetting agent
programme.

H2Pro TriSmart is registered as a non-microbial biostimulant under the latest EU Fertilizing
Product Regulation (FPR)(1009/2019).


https://icl-growingsolutions.com/turf-landscape/knowledge-hub/h2pro-trismart-registered-as-biostimulant/


https://www.aquaaid.eu/wp-content/uploads/2021/03/Wetting-Agent-research-2020_ENG.pdf


https://www.aquaaid.eu/wp-content/uploads/2021/03/Wetting-Agent-research-2020_ENG.pdf


Improvements of turf quality, turf colour, turf uniformity, turf density and NDVI were measured for
TriSmart treated plots in comparison with an untreated control, as well as significantly greater
volumetric moisture content percentage (VMC %).

2020 work carried out by Aquaaid in Europe looked at monthly applications of OARS vs several
other soil wetting agents including Trismart. Soil moisture was only measured at the 75mm depth.
Their results were that all the tested wetting agents resulted in a significantly higher soil moisture
balance compared to the untreated control plots.

1.2 Hydrahawk (Product 2)
HydraHawk is claimed to be a highly efficient soil surfactant that is works quickly and made from
100% natural materials.

HydraHawk helps water penetrate compact or arid soils, and contains unique natural surfactants
that help the plants utilize water and survive in extreme heat, drought and saline soils.

1.3
Tour Turf ELL (Product 3)
TourTurf® ELL Respond® Extreme Long Lasting is a unique wetting agent formulation designed
to work consistently with increased longevity within any turf grass rootzone. It is resistant to
microbial degradation in adverse climatic conditions, where temperatures are typically over 20°C.

TourTurf® ELL contains a specific blend of wetting agent technologies. The new innovative
residual long chain wetting agent is 20-35% longer than in other industry standard wetting agents.

The updated product formulation includes spreading and penetrating agents to ensure ELL
penetrates the turf grass surface quickly which means it is not readily subjected to the degrading
effects of UV light.

This penetration ability ensures the product enters the rootzone efficiently and does not bind itself
strongly to the organic matter in the top of the thatch layer. This in turn creates a firmer playing
surface with less moisture in the thatch layer.
1.4
Tricure (Product 4)
TriCure AD® is marketed as an advanced soil surfactant designed to prevent and control
hydrophobic soil conditions while maintaining optimum soil-water management. It works by
attaching to both soil and organic particles, reduces the surface tension of water, and attracts a thin
film of water close to the particle surfaces. This allows the optimum moisture to be held for plant
use while aiding water release and effective drainage.

Leinauer et al (2003-2004) looked at several wetting agents effects on sand-based rootzone
hydrophobicity and putting green turf appearance. The efficacy of wetting agents varied over depth
and was most pronounced at depths of 2.5 cm or less.
11. The products that most consistently reduced hydrophobicity (soil water repellency) were
Aqueduct, Brilliance, Cascade Plus, HydroWet, Primer Select and TriCure.
12. Products that consistently did the best job of reducing hydrophobicity also unfortunately had
potential (though limited potential) to cause some reduction in turf quality. However, this
decrease in quality was seen in a maximum of two out of nine locations.

Johnson and Leeper (2011) found that block polymer and modified block polymer wetting agents
(TriCure®, Revolution®) increased soil moisture and uniformity distribution by an average of 4.7
and 4.8%, respectively. A follow up study was conducted in 2011 on the same golf courses with a

modified treatment list. TriCure®, increased soil moisture by an average of 4.4%. Dispatch®
decreased soil moisture by 4.7%, and increased uniformity by 6.5%.

Baird et al in 2011 found that under extreme water stress conditions, Revolution® (Aquatrols)
performed the best of all products tested in alleviating turf drought symptoms and LDS incidence.
TriCure AD® was next best.

Recently Xiong and Anderson in 2020, evaluated 15 soil wetting agents for their effects on surface
tension, infiltration, and plant available water/retention.
1. Within 30 minutes after application and by 10 minutes into ponding, all the selected wetting
agents reached a steady infiltration rate.
2. Tricure fell into the second group that produced moderate amounts of plant-available water,
ranging from 7% to 9%.

Our own work on Tricure in 2022 has shown a reduction in dollar spot infection centres.

1.5 HydroForce Ultra (Product 5)
HydroForce Ultra is a newly discovered, innovative modified Block Co-Polymer surfactant
technology, altered to enhance adsorption to hydrophobic materials and to radically increase
wettability and responsiveness. The product has been extensively trialled by the US University
system (Purdue & Penn State) showing significant benefits.

By managing soil water more efficiently, HydroForce Ultra maximises turfgrass quality, health and
plant performance.


Our own work on HydroForce Ultra has shown a reduction in dollar spot infection centres (2022)
when this is used as a soil wetting agent. There is also a strong suggestion that it does improve turf
quality significantly under drought stress conditions as shown after 14 days of air drying at room
temperature.

Air Dried 14 Days. Hydroforce Ultra Treatment 5th from the LHS
1.6
Tour Turf REO (Product 6)
TourTurf® REO Respond® Extreme Organic Wetting Agent is the first 100% organic wetting agent
from TourTurf® to be approved for use in organic farming and is especially designed for the
turfgrass market.
1.7
Penterra (Product 7)

1.8
Control (8)
The control was untreated and water was just applied.
1.9 Gilba SA (Product 9).
Gilba SA is composed of an alkyl glucoside to block copolymer ratio of 4:1 whilst also containing a
percentage of salicylic acid (the exact amount is a trade secret).


1.9.1 Salicylic acid
Salicylic acid (SA) is a phenolic phytohormone and is found in plants with roles in plant growth and
development, photosynthesis, transpiration, ion uptake and transport. It is involved in endogenous
signaling against both biotic and abiotic stress, being an important plant hormone that regulates
many aspects of plant growth and development.

SA application has also reportedly increased heat tolerance (Larkindale, 2002). Induction of
defence-related genes and stress resistance in biotic stressed plants have also been reported
(Kumar, 2014).

SA is an effective SAR inducer, but its phytotoxicity precludes widespread use (Conrath et al, 2015).
While treating plants or suspension cells with high concentrations of SA or its functional analogs
directly induces defences, low concentrations elicit little to no response. Following subsequent
infection, however, defences are activated more rapidly and/or strongly (Conrath et al, 2006). This
priming phenomenon, also occurs in systemic leaves of plants exhibiting SAR.

Comparative work looking at the efficacy of salicylic acid and Acibenzolar-S-methyl (ASM) was
carried out into Alternaria solani, which is a destructive pathogen to tomato crops (Aslam et al,
2019). Foliar and seedling root dipping application of Bion and salicylic acid not only reduced the
disease severity but also enhanced the plant growth.

1.9.2. Turf specific research
The level of SA was shown to increase slightly after the first hour of heat stress in creeping
bentgrass (Larkindale and Huang 2005).


Work was carried out on perennial ryegrass by Shahgholi et al, 2013 examining the interaction
between Trinexapac ethyl and salicylic acid. Treatment of 0.27 g of salicylic acid had the maximum
height compared with other treatments which showed significant difference from control treatment
at 5% level. Trinexapac ethyl with concentrations of 0.8 and 1.2 ml/m2 and salicylic acid with
concentrations of 0.27 and 0.54 g/ m2 increased colour quality and chlorophyll content.

He et al 2005 examined the effects of SA at different concentrations (0, 0.1, 0.25, 0.5, 1, and 1.5
mmol) on heat tolerance of Kentucky bluegrass exposed to 46°C for 72 h in a growth chamber.
Among SA concentrations, 0.25 mmol was most effective in enhancing heat tolerance in Kentucky
bluegrass, which was manifested by improved regrowth potential following heat stress of 72 h and
maintenance of leaf water content at 77% during the 12-h stress period similar to that under normal
temperature conditions.

Hosseini, Kafi and Arghavani (2016) looked at the effect of salicylic acid on physiological
characteristics of Lolium grass (Lolium perenne cv. ‘Numan’) under drought stress. Salicylic acid
foliar application at 0.75 and 1.5 mm levels increased the content of chlorophyll a, b and reduced
electrolyte leakage, proline accumulation and antioxidant enzyme activity, which suggested that
salicylic acid can be used to reduce the negative impacts of drought stress.

1.10 Previous Research
Our 2020 work showed that salicylic acid applied to creeping bentgrass lead to increased root
growth and lateral root branching, better turf quality and faster and more consistent seed
germination.

By incorporating this the idea is to increase the ability of turf to better abiotic stress and drought
whilst also maintaining a strong and vigorous root architecture.

1.11 Tour Turf FTE (10)
TourTurf® FTE Respond® Extreme Fine Turf Enhancer is a new, innovative concept for
sustainable turfgrass management. The product is an advanced wetting agent which provides both
superior traditional wetting agent benefits such as water conservation, firm playing surfaces and
dry patch management, and at the same time helps to increase bent and fescue dominance in
turfgrass swards.

FTE Respond® Extreme has been scientifically formulated through three years of university
research to achieve the optimum chemical balance between a penetrant and a water conservation
agent.

The product improves the ability of the desired turfgrass species to germinate more successfully,
grow stronger roots and grow more evenly throughout the sward.


2.0 Materials and Methods
The practice putting green at Bonnie Doon G.C in Sydney, NSW was chosen to carry out this trial,
with the surface comprising approximately 85-90% creeping bentgrass (Agrostis tenuis var
MacKenzie). This was the second year of the trial after we started this in 2022/23 using the same
trial site.

A randomised complete block trial was marked out after using Edgar II for its design and layout.
The trial area comprised 10 treatments with 6 replicates, with one treatment being an untreated
control (60 plots in total). Each plot had a surface area of m2 with a 50 mm buffer around each.


Applications were made on 31st October 2023 with further applications being made on 23rd
November 2023, 11th December 2023, 7th February 2024 and the 4th of March 2024.

All treatments were applied in the label rate amount of water and then immediately washed in using
the in-ground irrigation system present at the site. This applied approximately 6mm of water.

The treatments were (1) H2Pro (ICL), (2) Hydrahawk (Geoponics), (3) Tour Turf ELL (Tour Turf),
(4) Tricure (Mitchell Products), (5) HydroForce Ultra, (6) Tour Turf REO (Tour Turf), (7) Penterra
(Geoponics), (8) Control, (9) Proprietary incorporating salicylic acid and (10) Tour Turf FTE (Tour
Turf).

Following application, the green was maintained as usual with fertilizer and irrigation applied when
required.
















Table 1. Rates and water volumes for products trialled.

Treatment
Active Ingredient
Rate
g(ml)/m2
Rate Product Kg
(L)/Ha
water volume
L/Ha
Comments
H2Pro
Trismart (1)
Dipropylene Glycol Methyl
Ether 5-10%; 3-5% 3-
butoxypropan-2-ol
2.5
25
800
Rate then
lowered to
10L/Ha
Hydrahawk
(2)

0.48
4.8
800

Tour Turf ELL
(3)
Blend of polypropylene and
polyethylene glycols
2
20
800

Tricure (4)
Reverse Block Co-polymer
1.25
12.5
800

HydroForce
Ultra (5)
Modified Block Co-polymer
12.5
12.5
800

Tour Turf REO
(6)
25-50% Sophorolipids
2
20
800

Penterra (7)
70% anionic blend; 30%
propylene glycol
0.48
4.8
800

Control (8)

-
-
800

Gilba (9)
Block co-polymer and APG
1.25
12.5
800

Tour Turf FTE
(10)
Co-block polyethoxylated
surfactants and soil
penetrants.
2
20
800


Assessments were as follows:
1. Turf Dark Green Colour Index (DGCI).
2. Turf Colour Quality.
3. Moisture Content at 37mm and 75mm.
4. Water Droplet Penetration Test.
5. Organic Matter by Loss on Ignition.



https://turfanalyzer.com/


2.1 Digital Image Analysis.
Turf Quality Analysis was carried out using a light box. The 0.75 x 0.75 m light box was positioned
in the centre of the plots and images taken using a Panasonic DMC-TZ80. On each sampling date
one image was taken per plot giving a total of 60 images.

The images were then analysed using Turf analyzer software to determine the DGCI, and Colour
Quality.

2.2 Moisture Content 37 mm and 75 mm.
Soil volumetric moisture content (VMC %) was recorded using two TDR 350 (Spectrum
Technologies) units fitted with 37 mm (1.5 inch) and 75 mm (3 inch) tines. Samples were taken
randomly in each plot with both units and the results logged.

This gave a total of 60 results at both depths on each sampling date (120 in total).

2.3 Water Droplet Penetration Test (WDPT).
19mm cores were taken three weeks after the 23rd of November application and dried at room
temperature for 14 days. A water droplet penetration time was then carried out on each individual
core at 0-2, 2-4 and 4-6 cm depth. This involved timing how long a drop of water took to penetrate
the soil profile at each respective depth. The test was repeated three times on each core at each
depth and the mean then recorded for the three readings.


2.4 Loss on Ignition (LOI).
Organic Matter Content variations over depth was assessed over a 6cm depth. 25cm cores were
taken from each plot and then shipped to Westgate Laboratories in Orange for independent testing.
The methodology involved removing the surface vegetation to a depth of 1cm and these samples
were then dried for 48 hours in a muffle furnace at 60°C.
The oven-dried samples were then ashed in a muffle furnace at 440°C for 4 hours. The substance
remaining after ignition is the ash. The ash content is expressed as a percentage of the mass of the
oven-dried sample.

% Ash Content = (C X 100)/B
where: C = ash weight in g, and B = oven-dried test specimen, weight in g.

The calculation to determine the amount of organic matter by difference, is as follows:
% Organic matter = 100.0 - D
where: D = ash content, %.

If these products were increasing root growth, organic matter contents would increase over the
control. The assumption was that as this was initially a clean USGA spec sand, any increases in
organic matter would be due to increases in root growth.

The Plots were monitored regularly using digital image analysis in combination with Image J.


2.5 Statistical Analysis
Statistical analysis was carried out using Studio R, agricolae package. All data were subjected to
two-way ANOVA (analysis of variance) to determine the Treatment effects. Treatment means were
separated using the Duncan’s multiple range test at the P = 0.05 level of probability.

3.0 Results.


3.1 Dark Green Colour Index (DGCI).
Over the duration of the trial, Digital Image Analysis showed no significant differences (P<0.05)
between the treatments.
Figure 1. Dark Green Colour Index. Values with different letters are significantly different (P < 0.05).




3.2 Colour Quality.
With Colour Quality, significant differences did exist between treatments (P<0.05).

Figure 2. Colour Quality. Values with different letters are significantly different (P < 0.05).








In all the graphs the solid red lines are applications times.













Figure 3. Colour Quality Values over Time.









3.3 Volumetric Water Capacity (VWC) %.
At 37 mm significant differences did exist between treatments (P<0.05). H2Pro Trismart (1)
had significantly higher soil moisture levels than Hydrahawk (2), Tour Turf ELL (3), Penterra
(7), and Tour Turf FTE (10). Penterra (7) was the only treatment to be significantly lower than
the control.
Figure 4. VWC % at 37 mm. Values with different letters are significantly different (P < 0.05).



At 75 mm, Penterra (7) continued to have a significantly lower moisture content than the Control
(8). Penterra (7) was also significantly lower than the Tricure (4) and H2Pro Trismart (1).




Figure 5. VWC % at 75mm. Values with different letters are significantly different (P < 0.05).


The Moisture results can be divided into two clear timeframes. From the trial start to 58 days and
then again from 99 days to 163 days. When we plot the results for 0-58 days at 37 mm vs the base
mean we get a clearer idea of how these perform. In this instance Tour Turf FTE (10) gives a highly
significant result (P ≤ 0.001), while H2Pro Trismart and Penterra (7) are significant at P < 0.05.


Figure 6. VWC % at 37 mm day 0-58. * (P < 0.05). ** (P < 0.01) and *** (P < 0.001)


















Figure 7. Fluctuations in VWC % at 37 mm day 0-58.






Figure 8. VWC % at 37 mm day over Time between 0 and 58 Days.



When we plot the results for 99-163 days at 37mm vs the base mean we see that the proprietary
surfactant plus salicylic acid (9) (P < 0.01), the Control (8) and Tour Turf FTE (10) (P < 0.05) are
the only treatments giving significant results.

Figure 9. VWC % at 37 mm day 99 - 163. * (P < 0.05). ** (P < 0.05) and *** (P < 0.001)














Figure 10. Fluctuations in VWC % at 37 mm day 99-163.










Figure 11. VWC % at 37 mm day over Time between 99 and 163 Days.



When we plot the results for 0-58 days at 75 mm vs the base mean we see the 0–58-day results
repeated with Tour Turf FTE (10), H2Pro Trismart (1) and Penterra (7) being significant at P < 0.01.
The proprietary surfactant plus salicylic acid (9) is significantly higher at P < 0.05.

Figure 12. VWC % at 75 mm day 0-58. * (P < 0.05). ** (P < 0.01) and *** (P < 0.001)













Figure 13. Fluctuations in VWC % at 75 mm day 0-58.




Figure 14. VWC % at 75 mm day over Time between 0 and 58 Days.



When we plot the results for 99-163 days at 75 mm vs the base mean we see the Control having
significantly higher soil moisture (P < 0.01). Tour Turf FTE (10) is also significantly higher (P <
0.05) and the proprietary mix (9) and Penterra (7) lower at (P < 0.05).

Figure 15.VWC % at 75 mm day 99 - 163. * (P < 0.05). ** (P < 0.01) and *** (P < 0.001)















Figure 16 Fluctuations in VWC % at 75 mm day 99-163.






Figure 17. VWC % at 75 mm day over Time between 99 and 163 Days.



3.4 Water Droplet Penetration Test (WDPT).
The H2Pro Trismart (1) treatment performed extremely well in the upper 1 cm of the rootzone and
gave consistent rapid movement away from the soil surface. This was significantly faster than the
Tour Turf FTE (10) and Hydrahawk (2) treatments.

Figure 18. WDPT at 1 cm. Values with different letters are significantly different (P < 0.05).


At a 2cm depth H2Pro Trismart had the lowest soil moisture. However, none of the treatments gave
significant differences in comparison to the Control at 2cm. The Tour Turf REO (10) and H2Pro
Trismart (1) treatments both moved water significantly faster than the Hydrahawk (2) treatment.









Figure 19. WDPT at 2 cm. Values with different letters are significantly different (P < 0.05).


At 3cm the proprietary treatment (9) was the only one to show a significantly lower soil moisture
content than the Control. The proprietary (9), HydroForce Ultra (5) and Tour Turf ELL (3) products
all had significantly lower water droplet penetration times compared to Hydrahawk.




















Figure 20. WDPT at 3 cm. Values with different letters are significantly different (P < 0.05).



















3.5 Organic Matter by Loss on Ignition.
HydroForce Ultra (5) was the only treatment that gave a significantly higher organic matter content
than the untreated Control. There were no significant differences between any of the other
treatments.

Figure 21. Organic Matter %. Values with different letters are significantly different (P < 0.05).











4.0 Discussion.
The first point is that these trials were not on stressed turf. Irrigation was never limiting so
improvements in drought tolerance or turf quality under stress are not valid. The closest we came to
that was the turf response to 14 days being air dried for the Water Droplet Penetration Test
(WDPT).

4.1 Colour Quality.
In the work of Leinauer [1], in 2 of 9 locations they observed a decline in turf quality with Tricure.
We also saw this over the duration of the trial. The Tricure Treatment and H2Pro Trismart, both
caused an initial decline in Colour Quality after application. In the case of the Tricure treatment this
was significant compared to the control (P < 0.05).

The initial drop off in turf Colour Quality after application with the H2Pro stopped with the follow
up applications as the rate was reduced from 25L/Ha to 10L/Ha.

Initially we proposed that this was due to a delay in washing the products in after the first
Treatment. In this instance due to irrigation issues there was three-to-four-hour delay before
irrigation was applied.

However, this pattern continued with a drop off in Turf Quality, after each application of Trismart
even when immediately watered in.

On this basis we would be wary of the label stating that Immediate watering-in is not necessary. On
the 31st of October the temperature was 29°C which would explain this initial phytotoxicity but the
temperatures on the other application days were 23.1 °C, 27.3°C, 23.5°C and 22.9°C. On all these

days watering in was immediate and there was still some degree of phytotoxicity. On this basis
despite the label stating otherwise we strongly suggest immediately watering in.

Over the trial duration the only treatments not to give significantly higher Colour Quality than
Tricure were the control and H2Pro Trismart.

4.2 Dark Green Colour Index (DGCI).
There were no significant differences between any of the treatments and the untreated control.

4.3 Volumetric Moisture Capacity (VMC %).
A key point relating to these results is what constitutes a good soil wetting agent? Does a good soil
wetting agent hold water in the soil profile or move it away from the surface?

The other issue is Plant Available Water (PAW). Even if a soil wetting agent holds water is this
available to the turfgrass?

Judging by the condition of the turfgrass when air dried for 14 days this would suggest that this isn’t
necessarily the case with all soil wetting agents.

Jiang et al [2] in a study of 21 soil wetting agents (including Tricure) found that some, such as
InfilTRX, could hold up to 1.4-times additional plant available water than others. Interestingly
Tricure was classed as only being able to hold moderate amounts of plant available water, ranging
between 7.5 % and 6.3%.


Over the duration of the trial Penterra consistently gave lower volumetric soil moisture contents at
both the 37- and 75-mm depth.

In contrast the Hydrahawk and H2Pro Trismart both gave the highest moisture contents over the
entire trial duration, and also when the two sample periods were looked at independently.

However, H2Pro has the added advantage of moving water away from the surface even in a
hydrophobic soil and does it quickly. HydroForce Ultra and Tour Turf REO also seem to be able to
move water quickly away from the surface and retain it in the top 1cm of the profile.

The fact that some of these soil wetting agents seem to hold water at the surface potentially has both
positive and negative impacts.

In our 2022 work we found that 7 out of 10 soil wetting agents caused softer greens. As we didn’t
measure soil moisture at 37 mm, we cannot conclusively say that this is the reason but Bauer [3]
found that firmness can be influenced by wetting agent applications in 2017 work.

The other key requirement from a soil wetting agent is uniformity. In this trial, Tour Turf FTE , the
proprietary mix and HydroForce Ultra appeared to give more consistent results at a depth of 37
mm. There were no ‘spikes’ or ‘troughs’ associated with soil moisture when these were used.











Figure 22. Uniformity between Blocks with Soil Wetting Agent Treatments





4.4 Water Droplet Penetration Test (WDPT).
The main finding of these results is that there is considerable variation between these wetting agent
chemistries. Some soil wetting agents are more persistent than others and taking the samples three
weeks after the 2nd treatment was well within the longevities stated on the labels.


The highest rate product in the trial: H20Pro performed well in this test, but the fact that the H2Pro
rate was dropped to 10L/Ha after the initial 25L/Ha suggests that if the same test was carried out
after this reduced rate, that it may not perform as well. Further work would be needed to confirm
this.

The ICL H2Pro Trismart treatment performed extremely well in the upper 1cm of the rootzone and
gave consistent rapid movement away from the soil surface. This was significantly faster than the
Tour Turf FTE and Hydrahawk treatments.

At a three-week testing interval post treatment there is a strong indication that the H2Pro Trismart,
HydroForce Ultra and Proprietary mix were all still working at the 1cm depth. This contrasts with
the Tour Turf FTE and Penterra treatments. Despite both performing well in regard to moving
water away from the surface that they had possibly stopped working after this three-week period.
At a 2cm depth H2Pro Trismart moved water quickly away from the surface. However, none of the
treatments were significantly faster than the untreated control at 2cm.

The Tour Turf FTE and H2Pro Trismart treatments both moved water significantly faster than the
Hydrahawk treatment.

At the 3 cm depth the proprietary (9) treatment was the only one to show a significantly lower soil
moisture content than the Control.

Overall, the results suggest that Hydrahawk is not working to move water away after 3 weeks, as it
gave the lowest Water Droplet Penetration times at all depths after this period.


The Proprietary mix, HydroForce Ultra and Tour Turf ELL products all had significantly lower
water droplet penetration times compared to the Hydrahawk treatment.


4.5 Organic Matter Content (%)
HydroForce Ultra) was the only treatment that gave a significantly higher organic matter content
than the untreated Control (P < 0.05). There were no significant differences between any of the
other treatments.

As the LOI was carried out over the entire core depth it is difficult to be conclusive as to where this
organic material was. The fact that the top 1cm was removed from the cores suggests that this is not
a result of the build-up of thatch. However, there is a strong reason to believe that it is due to
increased root growth at depth. Further work is needed to confirm this.


5.0 Conclusions.
Considerable variations exist in the performance of these wetting agents in this trial. Some of the
findings confirm findings from previous work, but soil wetting agent technology is advancing
rapidly. Now soil wetting agents don’t just “wet the soil” but can move water quickly away from the
soil surface, retain it in the profile or do both.

The ramifications of this work have raised a lot of questions regarding turf management.
Bearing in mind fungal pathogens require water does the fact that a soil wetting agent holds water
in the profile mean you are likely to get more root disease?


The flipside of this is if a soil wetting agent moves water away from the surface does this mean the
turfgrass is going to be more likely to suffer from moisture stress, especially on golf greens where
turfgrass where tends to be shallow rooted?

The pleasing finding from this work is that some of these products do seem to have plant health
benefits.

This 2023 work suggests that products like HydroForce Ultra can increase root growth. This was
also found in work by Indigo Specialty in 2020.

Figure 23. Significant Increase in root growth in a couch bowling green in May, 2020 in QLD.


Image 3. Control vs HydroForce Ultra comparative root growth.




Although not visible to the naked eye the Tricure and H2Pro Trismart treatments did appear to
cause phytotoxicity, and on this basis immediately watering in of these products is recommended.
This is despite the label for Tricure stating that immediate watering is not necessary.

If these were applied in hot periods and there was a delay in irrigation or watering in, the concern
would be that the level of phytotoxicity would become an issue.

Acknowledgments: We would also like to thank Craig Geeves, Course Superintendent at Duntry
Leagues Country Club and formerly 2IC at Bonnie Doon Golf Club for his help.
Funding: “There are no sources of funding to declare.”
Conflict of interest: "The author(s) declare no conflict of interest."
Data availability statement: "Data supporting these findings are available upon request."



https://turfgrass.ucr.edu/sites/default/files/2023-08/lds_and_drought_stress_2013.pdf


https://turfgrass.ucr.edu/sites/default/files/2023-08/lds_and_drought_stress_2013.pdf


http://dx.doi.org/10.1111/j.1365-3059.2005.01163.x
















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